Frequencies for first 10,000 rows of citrspop variable in natl1981 dataset :

 Population |
     size - |
   place of |
  residence |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        811        8.11        8.11
          3 |      1,175       11.75       19.86
          9 |      8,013       80.13       99.99
          Z |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016